Unconventional reservoirs are generally any reservoir (for example, hydrocarbon-carrying reservoir) in which special recovery operations (that is, recovery operations outside conventional operating practices) are employed. Unconventional reservoirs include reservoirs such as tight-gas sands, gas and oil shales, coalbed methane, heavy oil and tar sands, and gas-hydrate deposits, to name a few.
Shale reservoirs, for example, require large hydraulic fracture multistage design in order to maximize barrel of oil equivalent (BOE) well production. Methods to predict the propagation length, height, location and extent of these networks and their connectivities with both inherent natural fractures as well as induced micro- and nano-cracks are important components of reservoir storativity potentials and productivity predictions. Microseismic mapping is used to determine the location and geometry of the hydraulically fractured reservoir with its fracture network and connectivity. The fracture network represented by the microseismic event cloud is then approximated volumetrically in order to better correlate the network to the well performance. This so-called stimulated reservoir volume (SRV), or 3D volume of the created fracture network, is obtained from mapping of microseismic data and then related to the total volume of injected fluid and the well performance.